An asymmetric capture device for explosive bolt unlock protection

Abstract

An asymmetric capture device for explosive bolt unlocking protection, comprising: a shell, a shear screw, a buffer pad, a U-shaped block; the shell of the shell is a cube, one side of the shell is open; the buffer pad is installed at the top of the inside of the shell; the U-shaped block is installed below the buffer pad, the opening direction of the U-shaped block is consistent with the direction of the open side of the shell; the U-shaped block is fixed in the inner wall of the shell through the shear screw; the shell and the U-shaped block are both asymmetric structures. The application not only ensures the energy absorption effect of the capture device, but also effectively avoids the risk of separation failure caused by the rebound of the explosive bolt rod inserting the butt joint hole of the projectile, and solves the problem of protection of the excess material after the explosive bolt works.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aircraft separation device, in particular to an asymmetric capture device for explosive bolt unlocking protection, which is used for protecting the excess material generated after the explosive bolt works. BACKGROUND

[0002] Explosive bolts are widely used for unlocking the connection between the separation bodies of an aircraft. The internal pressure generated by the explosive in the explosive bolt causes the fracture of the explosive bolt structure at the pre-fracture section, thereby realizing the unlocking function. After unlocking, the screw rod part of the explosive bolt becomes an excess material with a large kinetic energy, which seriously threatens the safety of the aircraft product and greatly affects the reliability of the separation action. Therefore, a corresponding capture device must be used to store it in a limited space to avoid the risks and hazards caused by the excess material.

[0003] The structure of the capture device itself is generally a relatively closed space, or a relatively closed space is formed together with the cabin shell of the aircraft, and only a passing area is reserved for the explosive bolt screw rod. In order to quickly attenuate the kinetic energy carried by the explosive bolt screw rod, a corresponding energy absorption structure needs to be designed inside the capture device. The shear bolt type capture device fixes the U-shaped block in the inner wall of the capture device through a shear bolt. When the explosive bolt is unlocked, the screw rod part hits the U-shaped block together with the nut, and the shear bolt is sheared to achieve the energy absorption effect. This type of capture device has relatively low manufacturing cost, but cannot effectively avoid the risk of screw rod linear motion rebounding into the docking hole of the projectile, which will threaten the safety of the separation action. The tongue spring type capture device absorbs the kinetic energy of the explosive bolt screw rod through the elastic deformation of the tongue. After the explosive bolt screw rod passes through the tongue, it continues to move in a straight line until it rebounds after colliding with the capture device. The step surface of the screw rod and the nut will be reversely stopped by the tongue during the rebounding process. The capture device of this type is an integrated shell, the material is spring steel, the processing technology of the two tongue parts is complex, and the processing cost is relatively high. The energy absorption effect of the tongue depends entirely on the structure material, processing and assembly quality, and the relative angle between the nut on the explosive bolt screw rod and the tongue of the capture device has great randomness, which greatly affects the capture performance.

[0004] Although the above two types of explosive bolt capture devices have different energy absorption implementations, their structure forms are mirror-symmetric structures, and the explosive bolt axis is just on the symmetry plane of the capture device. It is just the above characteristics that make it difficult to effectively unify the energy absorption effect and the separation reliability of the capture device. SUMMARY

[0005] The present application provides an asymmetric capture device for explosive bolt unlocking, which is used to solve the problem of protecting the excess material after the explosive bolt works.

[0006] The application provides an asymmetric capture device for explosive bolt unlocking protection, comprising: a shell, a shear screw, a buffer pad, and a U-shaped block; wherein: the shell is a cavity structure with one side open; the buffer pad is installed at the top of the cavity; the U-shaped block is installed below the buffer pad, the opening direction of the U-shaped block is consistent with the direction of the open side of the cavity; the U-shaped block is fixed to the inner wall of the shell by a shear screw; the shell and the U-shaped block are asymmetric structures.

[0007] Further, the capture device is fixed to the upper side of the docking end frame by a connecting screw, the open side of the shell of the capture device is co-molded with the inner wall of the cabin section, and the shell of the capture device and the inner wall of the cabin section form a closed space.

[0008] Further, the docking frame is connected and fixed to the mother cabin docking frame by an explosive bolt, and the closed space contains the nut, spring washer, and flat washer of the explosive bolt.

[0009] Further, the end face of the U-shaped block on the side facing the explosive bolt has an included angle alpha with the axis of the explosive bolt, and the end face of the U-shaped block on the side away from the explosive bolt is perpendicular to the axis of the explosive bolt.

[0010] Further, the two inner side walls of the shell along the axis direction of the explosive bolt have an included angle beta with the axis of the explosive bolt, and beta is less than <arctan(1 / μ), where μ is the friction coefficient of the contact surface between the inner wall of the shell of the capture device and the U-shaped block.

[0011] Further, the included angle alpha and the included angle beta satisfy the following relationship: alpha = 90°-beta.

[0012] Further, the U-shaped block is fixed to the inner wall of the shell by a shear screw in the following way: the two sides of the U-shaped block opposite to the inner wall of the shell each have two rectangular grooves, the shell has screw holes corresponding to the rectangular grooves, the shear screw extends into the rectangular groove from the outside of the shell through the screw hole to fix the U-shaped block, the length of the shear screw extending out of the inner wall of the shell is l, the length of the rectangular groove is 2l-2.5l, the width is 1.3l-1.5l, and the depth is 2l.

[0013] Further, the position relationship between the two rectangular grooves on the same side of the U-shaped block and the corresponding shear screw is that the distance between the axis of the shear screw close to the explosive bolt and the lower end face of the corresponding rectangular groove is a, and the distance between the axis of the shear screw away from the explosive bolt and the lower end face of the corresponding rectangular groove is b, which satisfies the following condition: b>a.

[0014] Further, the buffer pad is in the form of a honeycomb energy absorption structure, a symmetric section of the buffer pad has a distance △d from the axis of the explosion bolt, and the buffer pad and the U-shaped block have a gap h in the direction of the axis of the explosion bolt.

[0015] Further, the axial minimum distance L1 of the U-shaped block from the top end surface of the explosion bolt, the axial total thickness L2 of the docking end frame of the mother cabin and the docking end frame satisfy the following relationship: L1>3l, L1>L2.

[0016] Compared with the prior art, the present application has the following advantages:

[0017] (1) The present application further absorbs the impact energy of the screw end of the explosion bolt through the friction between the U-shaped block and the inner wall of the capture device shell, thereby increasing the energy absorption path and effect of the capture device.

[0018] (2) The present application can effectively avoid the risk of the screw end of the explosion bolt colliding and rebounding into the through hole of the ear piece of the docking end frame, thereby improving the reliability of the separation and unlocking action. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic diagram of the asymmetric capture device structure for explosion bolt unlocking protection of the present application;

[0020] Figure 2 is a schematic diagram of the asymmetric capture device installation of the present application for explosion bolt unlocking protection;

[0021] Figure 3 is a sectional view of the asymmetric capture device installation of the present application for explosion bolt unlocking protection.

[0022] In the figure, 1 is an outer shell, 2 is a shear screw, 3 is a buffer pad, 4 is a U-shaped block, 5 is an explosion bolt, 6 is a docking end frame of a mother cabin, 7 is a docking end frame, 8 is an inner wall of a cabin section, 9 is a connecting screw, 10 is a nut, 11 is a spring washer, 12 is a flat washer, A is a cabin section separation interface, B is an explosion bolt pre-fracture surface, L1 is the axial minimum distance of the U-shaped block 4 from the screw end of the explosion bolt 5, and L2 is the axial total thickness of the docking end frame 6 of the mother cabin and the docking end frame 7. DETAILED DESCRIPTION

[0023] The present application proposes an asymmetric capture device for explosion bolt unlocking protection, which comprises an outer shell 1, a shear screw 2, a buffer pad 3, and a U-shaped block 4.

[0024] Figure 1As shown, the shell of the outer shell 1 is a cavity structure with one side open, and the shell is, for example, a cube with one side open; the cushion 3 is installed at the top end inside the shell; the U-shaped block 4 is installed below the cushion 3, and the opening direction of the U-shaped block is consistent with the direction in which the side of the shell is open; the U-shaped block 4 is fixed to the inner wall of the outer shell 1 by shear screws 2; the outer shell 1 and the U-shaped block 4 are both asymmetric structures.

[0025] Figure 3 As shown, the specific way in which the U-shaped block 4 is fixed to the inner wall of the outer shell 1 is that the two opposite sides of the U-shaped block 4 each have two rectangular grooves, the shell 1 has screw holes corresponding to the rectangular grooves, and the shear screws 2 are inserted into the rectangular grooves from the outside of the outer shell 1 through the screw holes to fix the U-shaped block 4.

[0026] Figure 2 As shown, the bottom of the outer shell 1 has protruding feet on both sides, and two screw holes are formed in each of the two feet. The capture device is fixed to the upper side of the docking end frame 7 by connecting screws 9, and the open side of the outer shell 1 of the capture device is co-molded with the inner wall 8 of the cabin section. The outer shell 1 of the capture device and the inner wall 8 of the cabin section form a closed space for accommodating the explosion bolt. The explosion bolt 5 includes a nut 10, a spring washer 11, and a flat washer 12. The nut 10 is rotatably connected to the stud of the explosion bolt 5, and the nut 10 is sequentially provided with the spring washer 11 and the flat washer 12.

[0027] The docking frame 7 is connected and fixed to the mother cabin docking frame 6 by the explosion bolt 5. The contact interface between the mother cabin docking end frame 6 and the docking end frame 7 serves as the separation unlocking interface A of the aircraft. The contact surface between the bottom surface of the mother cabin docking end frame 6 and the explosion bolt 5 serves as the pre-fracture surface B of the explosion bolt. The closed space is used to accommodate the nut 10, the spring washer 11, and the flat washer 12 of the explosion bolt 5 to prevent the screw rod and related fasteners of the explosion bolt 5 from entering the cabin section after the explosion bolt 5 works.

[0028] The outer shell 1 of the capture device is made of aluminum alloy 2A12 material, and the execution standard is GB / T3880.2-2012. The outer shell 1 has an asymmetric structure. The two side walls of the cuboid shell of the outer shell 1 along the axis direction of the explosion bolt 5 have non-uniform wall thicknesses, and the two inner side walls have an included angle β with the axis of the explosion bolt 5, and β is less than <arctan(1 / μ), where μ is the friction coefficient of the corresponding contact surfaces between the inner wall of the outer shell 1 of the capture device and the U-shaped block 4.

[0029] The two side walls of the outer shell 1 each have two groups of four threaded holes for mounting and fixing four shear screws 2. The shear screws 2 are mounted from the outside to the inside of the outer shell 1. The length of the inner wall of the outer shell 1 protruding out of the shear screw 2 is l.

[0030] The shear screw 2 is a standard part, and the execution standard is GB / T67-2008 “Slotted Pan Head Screw”. The performance grade is not less than 4.8.

[0031] The U-shaped block 4 is made of steel material and adopts an asymmetric structure, the end face of the U-shaped block 4 on the side facing the explosion bolt 5 has an angle a with the axis of the explosion bolt 5, and the angle a can satisfy a = 90°-β, and the end face of the U-shaped block 4 on the side away from the explosion bolt 5 can be perpendicular to the axis of the explosion bolt 5.

[0032] The two side faces of the U-shaped block 4 in contact with the inner wall of the shell 1 are in clearance fit, and the preferred fit tolerance is H8 / f8.

[0033] Two groups of four rectangular grooves are formed in the two side faces of the U-shaped block 4 in the corresponding regions of the shear screw 2, the length of the rectangular grooves is 2l-2.5l, the width is 1.3l-1.5l, and the depth is 2l, and the dimensional tolerance is executed according to GB / T1804-m level.

[0034] The relative positions of the two rectangular grooves on the same side face of the U-shaped block 4 and the corresponding shear screw 2 are different, the distance between the axis of the shear screw 2 on the side close to the explosion bolt 5 and the lower end face of the corresponding rectangular groove is a, the distance between the axis of the shear screw 2 on the side away from the explosion bolt 5 and the lower end face of the corresponding rectangular groove is b, and the distances a and b satisfy the following conditions: b>a, so that when the U-shaped block 4 moves inside the shell 1, the two shear screws 2 on the side closer to the explosion bolt 5 are cut off first, and the two shear screws 2 on the side away from the explosion bolt 5 are cut off later.

[0035] The buffer pad 3 is bonded to the inner top of the shell 1 and adopts a honeycomb energy absorption structure, the symmetric plane of the buffer pad 3 has a deflection distance △d from the axis of the explosion bolt 5, and the buffer pad 3 and the U-shaped block 4 have a gap h in the axial direction of the explosion bolt 5.

[0036] The axial minimum distance L1 between the U-shaped block 4 and the top end face of the explosion bolt 5, and the total thickness L2 of the docking end frame 6 and the docking end frame 7 satisfy the following relationship: L1>3l, L1>L2.

[0037] The capture device can realize the separation protection of the screw rod of the explosion bolt 5. The contact interface of the docking end frame 6 and the docking end frame 7 is the separation unlocking interface of the aircraft, and the docking end frame 6 and the docking end frame 7 are connected and fixed by a plurality of groups of explosion bolts 5, nuts 10, spring washers 11 and flat washers 12 in the circumferential direction. The capture device is fixed inside the docking end frame 7 by four connecting screws 9, the capture device is co-molded with the inner wall 8 of the cabin section, thereby forming a local closed space, and avoiding the screw rod and related fasteners of the explosion bolt 5 from entering the cabin section after the explosion bolt 5 works.

[0038] The U-shaped block 4 is fixed in the inner wall of the capturing device shell 1 by four shearing screws 2, and the buffer pad 3 is bonded at the bottom end of the shell 1. After the explosion bolt 5 works, the screw rod of the explosion bolt 5 containing high-speed kinetic energy and the nut 10, spring washer 11 and flat washer 12 are first collided with the U-shaped block 4 along the axis direction of the explosion bolt 5. In order to avoid the rebound of the screw rod into the threaded hole of the butt joint end frame 7 after the collision, the shell 1 and the U-shaped block 4 of the capturing device are asymmetric structures. Since the inner side wall plane of the U-shaped block 4 is at an angle β with the movement direction of the explosion bolt 5, after the collision, the rebound direction of the screw rod of the explosion bolt 5 will deviate from the axis of the threaded hole of the butt joint end frame 7, so as to avoid the rebound of the screw rod into the threaded hole of the butt joint end frame 7, and effectively improve the reliability of the separation process.

[0039] Due to the existence of the angle β, the impact force acting on the U-shaped block 4 during the impact of the screw rod containing high-speed kinetic energy will have a component perpendicular to the inner wall surface of the shell 1, generating a friction force that hinders the movement of the U-shaped block 4. At the same time, the U-shaped block adopts a step-by-step scheme to successively shear the four shearing screws 2 to offset the impact of the screw rod impacting the U-shaped block. After that, the U-shaped block still has a small amount of kinetic energy, which further collides with the buffer pad and is absorbed by the buffer pad.

[0040] The present application not only ensures the energy absorption effect of the capturing device, but also effectively avoids the risk of separation failure caused by the rebound of the explosion bolt screw rod into the butt joint hole of the projectile.

Claims

1. An asymmetric capture device for explosive bolt unlock protection, characterized by, It comprises: a shell (1), a shear screw (2), a buffer pad (3), a U-shaped block (4); wherein; the shell (1) is a cavity structure with one side open; the buffer pad (3) is installed at the top end inside the shell; the U-shaped block (4) is installed below the buffer pad (3), and the opening direction of the U-shaped block (4) is consistent with the direction of the open side of the shell; the U-shaped block (4) is fixed to the inner wall of the shell (1) by the shear screw (2); the shell (1) and the U-shaped block (4) are both asymmetric structures; the end face of the U-shaped block (4) towards the explosion bolt (5) side has an angle α with the axis of the explosion bolt (5), and the end face of the U-shaped block (4) away from the explosion bolt (5) side is perpendicular to the axis of the explosion bolt (5); the two inner side wall planes of the shell (1) along the axis direction of the explosion bolt (5) have an angle β with the axis of the explosion bolt (5), and β is less than <arctan(1 / μ), where μ is the friction coefficient of the contact surface between the inner wall of the shell (1) and the U-shaped block (4); the angle α and the angle β satisfy the following relationship: α = 90°-β.

2. The capture device of claim 1, wherein, The capture device is fixed to the upper side of the docking end frame (7) by the connecting screw (9), the open side of the shell (1) is co-molded with the cabin inner wall (8), and the shell (1) and the cabin inner wall (8) form a closed space.

3. The capture device of claim 2, wherein, The docking end frame (7) is connected and fixed to the parent cabin docking end frame (6) by the explosion bolt (5), and the closed space contains the nut (10), spring washer (11), and flat washer (12) of the explosion bolt (5).

4. The capture device of claim 1, wherein, The U-shaped block (4) is fixed to the inner wall of the shell (1) by the shear screw (2) in the following way: The U-shaped block (4) has two rectangular grooves on each side opposite to the inner wall of the shell (1), the shell (1) has screw holes corresponding to the rectangular grooves, the shear screw (2) extends into the rectangular groove through the screw hole from the outside of the shell (1) to fix the U-shaped block (4), the length of the shear screw (2) extending out of the inner wall of the shell (1) is l, the length of the rectangular groove is 2l-2.5l, the width is 1.3l-1.5l, and the depth is 2l.

5. The capture device of claim 4, wherein, The position relationship between the two rectangular grooves on the same side of the U-shaped block (4) and the corresponding shear screw (2) is that the distance between the axis of the shear screw (2) close to the explosion bolt (5) side and the lower end face of the corresponding rectangular groove is a, and the distance between the axis of the shear screw (2) away from the explosion bolt (5) side and the lower end face of the corresponding rectangular groove is b, which satisfies the following condition: b>a.

6. The capture device of claim 3, wherein, The buffer pad (3) is in the form of a honeycomb energy-absorbing structure, the symmetric section of the buffer pad (3) has a deflection distance △d from the axis of the explosion bolt (5), and the buffer pad (3) and the U-shaped block (4) have a gap h in the axial direction of the explosion bolt (5).

7. The capture device of claim 4, wherein, The axial minimum distance L1 between the U-shaped block (4) and the top end face of the explosion bolt (5), and the total thickness L2 of the axial direction of the parent cabin docking end frame (6) and the docking end frame (7) satisfy the following relationship: L1>3l, L1>L2.

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